ABSTRACTThe spectacular occurrence of a sinkhole near the Gulf Coast of Florida engulfed a well drilling rig, a water truck, and a load of PVC pipe on a trailer, all within less than 10 minutes. The 150‐foot diameter sinkhole, which was initially dry and extended to a depth of 59 feet below mean sea level, developed suddenly on September 19, 1974. This occurred during the drilling of a 6‐inch well in Hernando County, about 5 miles inland from the Gulf of Mexico at a land surface elevation of 11 feet above mean sea level. The sinkhole which displaced 6500 cubic yards began to develop when the drill bit entered a cavity at a depth of 202 feet. Numerous satellite sinks ranging up to 20 feet in diameter occurred simultaneously with the develop‐ ment of the parent sink. Within 24 hours, ground‐water discharge into the parent sink from the shallow, unconfined and unconsolidated aquifer had filled the sink to an elevation of 8 feet above mean sea level. The total esti‐ mated replacement cost of the equipment lost in the sinkhole is